Homeostasis Flashcards
What is a tissue
A tissue consists of a series of similarly specialised cells that perform a common function
What are the four major categories of tissues
Epithelial , muscular , connective,nervous
What are epithelial cells and what do they help with in the body
Consist of tightly packed cells forming a continuous layer.
They serve in protection (skin)
Secretions (glands)
Absorption (Lines GIT)
Excretion and filtration (kidney)
What is connective tissue and what functions does it serve
They are relatively sparse cells in an extracellular matrix
Binds organs and provides support and protection in :
Fibrous tissue
Adipose tissue
Cartilage
Bone
Blood
What is muscular tissue and what functions does it serve and what are the three types
Muscle tissue is composed of muscle fibres , it helps in movement.
The three types include:
Skeletal muscle
Smooth muscle
Cardiac muscle
What is homeostasis
The relative constancy of the body’s internal environment.
How is homeostasis maintained
It is maintained around a set point via negative feedback
Which systems control homeostasis
The nervous system
The endocrine system
What is the function of Oligodendrocytes
They from the myelin sheath around the axons of the neurons spreading its membrane around the axon which insulates and increases the speed of conduction
What is the difference between oligodendrocytes and Schwan cells
Oligodendrocytes are in the cns whereas schwan cells are in the peripheral nervous system
What is the function of astrocytes
They provide support to the neurones
Structural
And metabolic (buffer the amount of k+ in the extracellular space)
They also have foot processes
What is the function of microglia
They are the immune cells of the cns
What is the four parts of the neuron
Cell body
Dendrites
Axon
Axon terminal
What is the main function of
Cell body
Contains
Nucleus
RER
Mitochondria
What is the main function of
Dendrites
Outgrowths from cell body that receives inputs from other neurons
What is the main function of
Axon
Nerve fiber extending from axon hillock which carries the action potential , contains microtubules
What is the main function of
Axon terminal
Contains the synapse which works by releasing neurotransmitters
What are the three functional class of neurons
Afferent
Efferent
Interneurons
What is the function of afferent neurons? (Sensory)
Transmit information to the CNS and have sensory receptors at the peripheral end
What is the function of afferent neurons?
(Motor)
Transmit information from the CNS to the effector organs or other neurons .
What is the function of interneurons?
Transmit information from neuron to neuron , are exclusively in the CNS, they make up most neurons
What does the cns consist of
Brain and spinal cord
What does the peripheral nervous system consist of
Nerves and ganglia outside the cns
What is the function of the Endocrine system?
The Endocrine system works in coordination with the nervous system to maintain homeostasis
Explain the processes for peptide and steroid hormones
Peptide hormones bind to a receptor at the cell membrane, causing a second messenger, cascade, e.g. production of Camp e.g.parathyroid hormone. They cannot cross the cell membrane
Steroid hormones are lipophilic and therefore can cross cell membranes. The receptor can be within the cell, steroid hormones result in hormone receptor complexes that activate DNA and protein synthesis. steroid hormones can also have receptors at the cell surface acting through second messenger systems e.g. aldosterone 
